You're correct. Somewhere around the Net there's a DOS program that produces voice output by playing strange games with the PC speaker; the volume is very low, but the fidelity is quite good.

(It's still nothing compared to the 8-bit DAC I got to play with on the C1P, especially with the program that built four 6-bit audio waveforms and summed them before writing to the DAC... why do PCs always look like a step backwards?)